Diagnostic Accuracy of CBNAAT for Detection Of Mycobacterium Tuberculosis In Pulmonary Tuberculosis patients.

Dr.Virender Singh; Dr.Deepika Dewan; Dr. Lubna Ashraf Mir; Dr.Gopal Dutt; Dr.Kavi

Volume : VIII, Issue : V, May - 2019

Diagnostic Accuracy of CBNAAT for Detection Of Mycobacterium Tuberculosis In Pulmonary Tuberculosis patients.

Dr. Virender Singh, Dr. Deepika Dewan, Dr. Lubna Ashraf Mir, Dr. Gopal Dutt, Dr. Kavi

Abstract :

Background: Mycobacterium tuberculosis remains to be one of the most significant causes of death from an infectious agent. CBNAAT (Cartridge Based Nucliec Acid Amplification Test) also known as Gene Xpert MTB/RIF assay is a novel integrated diagnostic device for the diagnosis of tuberculosis and rapid detection of RIF resistance in clinical specimens. Material and Methods: A cross sectional study was conducted at CHC Katra, a block level Hospital of District Reasi, Jammu from January 2018 to December 2018. The study included the entire population above ten years of age who were presumptive pulmonary tuberculosis patients as per Revised National Tuberculosis Control Programme (RNTCP) guidelines. Patients with history of receiving antituberculous drugs within 3 months before enrollment were excluded. Sputum smear for acid–fast bacilli was performed on fresh specimen at the designated microscopy centre of CHC Katra Hospital. The positive smears were sent for CBNAAT.Sputum specimens of the smear negative patients who were strongly suspected for PTB were also sent for CBNAAT. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of Xpert was assessed in relation with sputum smear microscopy. Results: Out of 305 presumptive cases of pulmonary TB who were tested for sputum by smear microscopy, acid fast bacilli were detected in 17 cases only giving a sensitivity of 5.6%. A total of 55 sputum specimens were sent for Xpert MTB/RIF inclusive of 17 patients positive on sputum smear microscopy. It yielded positive result in 24 specimens (with sensitivity of 43.63%). Senstivity and Specificity of CBNAAT was 100% and 81.6% respectively. Positive and Negative Predictive Value of CBNAAT was 70.8% and 100% respectively. Conclusion: Xpert MTB/RIF is highly sensitive and good specificity in detecting M. tuberculosis from respiratory specimens and very valuable in making a rapid diagnosis